CATCH STRATEGIES FOR THE PACIFIC SARDINE (SARDINOPS SAGAX)

In this paper we develop a model of the long-term prospects for the Pacific sardine (Sardinops sagax) in which the surplus growth of the stock is influenced by random fluctuations. This can have an enduring effect partly through a serial correlation in the environmental disturbances, but also, and more importantly, because the effect of these random disturbances is related to the size of the stock itself. We use the model to generate fluctuations in the sardine stock to compare alternative fishing strategies: (i) constant escapement; (ii) constant exploitation rate; and (iii) a hybrid of the two. We find that strategy (i) results in greater catches per year and greater variability than (ii). The hybrid, (iii), results in greater catches and greater variability than (i). We conclude that the model supports the existing management of the U. S. Pacific sardine fishery.